1. Field of the Invention
The present invention is directed to a method for operating a postage meter and addressing machine of the type including steps for entering a postage value, steps for comparing a print image, and steps for starting and completing printing of the print image. The method is suited for a xe2x80x9cclosedxe2x80x9d system, particularly for individual users of postage meter machines.
2. Description of the Prior Art
Conventionally, franking and addressing have been mainly implemented by separate machines. The franking imprint, which is usually to be applied to a filled envelope, requires a specific printing technology that is not suited for address printing. For applications wherein envelopes are to be both franked and addressed by machine, the use of two separately operating machines in the mail output processing is a considerable investment. Two machines also require corresponding placement areas as well as twice the maintenance outlay.
More recent postage meter machines utilize digitally operating printer units. For example, the T1000 and JetMail postage meter machines offered commercially by Francotyp-Postalia AG and Co. (Postalia, Inc. in the United States), are the first to use a thermal transfer printer and an ink jet printer, respectively. It is thus fundamentally possible also to print addresses on a filled letter, but only in the area of the franking stamp. The postal regulations of most countries prohibit printing address information at the same level on the envelope or package as the franking imprint. Printing in the address area of the envelope reserved for the address of the mail recipient using the same printhead as is used to print the franking imprint at its designated location on the envelope is not possible with such machines since the printing width of the printhead is inadequate to print at both locations.
Another obstacle for the implementation of franking imprints and address printing with the same print unit has hitherto been the requirement of the postal authorities for a specific color for the franking imprint (usually orange), often paired with a requirement for fluorescence. Franking imprints with such a color could not be copied true to the original on conventional color copiers. Until recently, this constituted a certain protection against the copying of franking imprints for illicit purposes. Due to progress that has been made in color copiers and color printers in the meantime, such a measure can no longer be considered a serious impediment to producing counterfeit, unpaid imprints.
In the context of letter distribution systems, moreover, there is a need for an optimally high-contrast color, specifically for the address printing, that should be automatically (machine) scannable with high dependability. The letter is controlled through the letter sorting system of the mail distribution centers on the basis of the scanned address data. The printing devices of conventional postage meter machines, however, only print their imprints with the postal orange color. The need for machine-readability in combination with high processing speed is met best by the color black.
Digital postage meter machines of the type described above are not absolutely secure. Future color copiers will be able to duplicate a franking imprint that can no longer be distinguished from an original imprint. Based on estimates, an annual loss of approximately $200 million is incurred by the United States Postal Service (USPS) due to fraud. The USPS has therefore compiled a specification catalog with requirements which must be met by the design of future postage meter machines (information-based indicia program IBIP) published on Jun. 13, 1996. It is proposed therein that certain data be cryptographically encoded and be printed on the letter in the form of a digital signature. Every imprint thus differs from every other imprint. The scanning of this information and the decryption thereof enables the postal authority to recognize counterfeit franking imprints. These requirements are differentiated according to the type of franking means employed to produce the imprint. An imprint wherein a specific set of franking data is involved in the encryption is proposed for stand-alone machines. At the postal side, it would become necessaryxe2x80x94after decryption of the imprintxe2x80x94to implement a comparison with all previous imprints contained in a data bank. If an identical imprint is discovered by this comparison, this is a counterfeit. The outlay for a complete archiving of all imprints and the implementation of a comparison under real-time conditions, however, would be enormous.
Conventional postage meter machines, which usually only print a franking stamp in red, are also referred to as xe2x80x9cclosed systemsxe2x80x9d and, differing from what are referred to as xe2x80x9copen systemsxe2x80x9d (PC frankers), do not incorporate the corresponding letter address into the encryption. A security module with progressive crypto-technology and a secured housing in which data of the data center can be stored, however, are still required for such xe2x80x9copenxe2x80x9d systems.
U.S. Pat. No. 5,200,903 (European Application 298 775) discloses a postage meter machine that prints the franking stamp as well as the address. For low mail volume, the outlay for the letter transport relative to the stationarily arranged printhead is disadvantageous. A further deficiency is that the printing of both images is to be implemented in only a single motion phase of the letter. This requires a printhead that is of a width corresponding to the widths of the two images of the franking stamp and the address field and the space lying therebetween. This is already 10 cm given a standard letter and up to 20 cm given other letter formats. A correspondingly wide thermal printhead can in fact be fundamentally manufactured, but would be disproportionately more expensive than a standard head of approximately 3-6 cm. Such widths cannot be implemented at all in ink jet printhead technology in the foreseeable future for manufacturing related reasons (yield). Another factor is that a constant spacing from the printing surface is required for an ink jet printhead and this would be a problem to maintain over a wide area, given the generally uneven surface of a filled envelope.
German OS 196 05 015 discloses an apparatus for printing on a print medium standing on edge, wherein two recesses are contained in a guide plate, one for the franking imprint and one for the address printing. The printhead can be adjusted between the two recesses. Even when the adjustment of the printhead is initiated immediately after the first print image was produced, a certain time passes until the printhead has assumed its second position. During this time, however, the letter continues to move, so that only a very limited letter length is available for the second imprint. Print images which overlap in the vertical direction are generally excluded from this solution.
U.S. Pat. No. 4,868,757 likewise discloses a solution for printing a franking stamp and address field with one printer unit. The letter is automatically drawn into the printing station. After assuming its printing position, the printhead is automatically lowered onto the letter surface until physical contact has been produced. The printhead is arranged so as to be movable in a direction in order to be able to reach the entire print field. The outlay for the automatic letter draw-in is a disadvantage of this solution. The use of an ink jet printhead is also precluded, again because an ink jet printhead requires a nearly constant distance of the printhead nozzles from the letter surface, even if the letter surface exhibits considerable irregularities. The franking imprint, moreover, is not counterfeit-proof.
In U.S. Pat. No. 5,025,386, an envelope is not only transported in one direction but also a printhead is moved back and forth in the same direction and opposite thereto in order to print a line within a window. The printing device must be orthogonally adjusted for printing a further line.
Orthogonal adjustment capability of a printhead without requiring a constant back and forth movement of the printhead for line printing was already disclosed in U.S. Pat. No. 5,467,709. For the printing itself, the printhead dwells in a first printing position while the envelope is transported with a transport mechanism. A second printing position, however, is only approached for alternative printing on franking tapes. Printing of franking and address data on an envelope does not occur with such a postage meter machine. The letter transport mechanism needed in addition to the adjustment mechanism, and without which the printing would be impossible is disadvantageous.
The techniques which are standard in commercially obtainable ink jet printers, particularly the shuttle principle for the back and forth motion of the printhead in the x-direction, were united with a postage meter machine without a letter transport mechanism in U.S. Pat. No. 5,611,630. By means of an eccentrically positioned carrier rod, a slight lift in the y-direction can be exerted on the printhead in order to print a second print frame with an offset of half a dot spacing. This technique is time-consuming during printing and, moreover, is not suited for additionally printing in a second print position, for example a mailing address, at a greater distance from the first.
German PS 40 18 166 discloses a franking module for a personal computer for users with low mail volume, the franking module, which allows franking as well as addressing of envelopes, being arranged in an envelope-receiving slot of a drive insert. Such a franking module is surrounded by a secured housing and has the same circuitry as a postage meter machine wherein the letter transport means is eliminated. By utilizing the franking module, the debiting of the franking and the printing of the franking stamp image cannot be externally manipulated. The address data are read from a memory administered by a personal computer and are supplied to the franking module via the internal information routing network. Such a franking module can only be operated in combination with the personal computer and is not suited for use in a stand-alone machine. Moreover, only a standard envelope fits into the delivery slot. The printing mechanism itself is not disclosed in German PS 40 18 166. Given a digital printing process, it cannot be determined with certainty whether the printed franking stamp image is merely an unpaid copy of an earlier imprint that was combined with a desired, other address.
An object of the present invention is to provide an economical stand-alone machine for lower mail volumes wherein the functions of franking and addressing outgoing mail are united in one machine and wherein the use of an inexpensive ink jet printhead is enabled. Both imprints should ensue directly on the letter surface. The solution should also assure a constantly good print quality for filled letters with an uneven surface. The operation of the machine should be controlled such that the processing time is minimized.
The security of the franking imprint against fraudulent manipulation should meet the (expected) future, strict demands of the postal authorities and should simultaneously enable a low-outlay verification of the genuineness of every imprint.
Inventively, a prompt to enter a shipping destination address, generation of the print image for the address field, starting of the printout of the address and control of the information processes for generating a security imprint ensue parallel in time with specific motion sequences of the printhead. The motion sequences of the printhead include the executive sequences when printing the address and/or the executive sequences when positioning the printhead preceding the printing. The information processes particularly relate to a generation of a digital signature. The digital signature is implemented before the printing of the franking stamp image parallel in time to the first output of the printout of the address and corresponding motion sequences of a printhead, so that a time-optimized execution is achieved overall when printing the address and the franking stamp image.
A microprocessor processes further functions or tasks in a time-nested manner during the time span from the start to the completion of the printout of the shipping destination address, as may be needed in preparation for the printing of the franking stamp image.